Dear Dieter, i'm glad to hear about your interest.
Concerning the price: you pricelist includes different rack cases having different cost, items such as Hi-End VCO, blue-LED versions of modules and other items. Offering high-fidelity might be just another option. (Finally it can be just another OEM items such as CEM chips, LEDs, sockets etc)
I'm not a professional engineer, but you are. So, i believe you can find some more cost-effective components with quality close to this particular Analog Devices component but higher then just plain TL064...
Anyway, thanks for your interest.
Best regards,
Dmitry

--- In Doepfer_a100@yahoogroups.com , <yahoo@...> wrote:
>
> Dmitry,
>
> thank you for the detailed report. That was interesting for me too.
> Unfortunately the OP470 is very expensive (~ Euro 15 here in Germany) and
> would increase the price of the modules clearly.
>
> Best wishes
> Dieter Doepfer